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ARS Home » Northeast Area » Washington, D.C. » National Arboretum » Floral and Nursery Plants Research » Research » Research Project #446441

Research Project: Increasing the Sensitivity and Reliability of Detecting Select Agent Pathogen Ralstonia solanacearum race 3 Biovar 2 in Latently Infected Geraniums

Location: Floral and Nursery Plants Research

Project Number: 8020-22000-052-002-I
Project Type: Interagency Reimbursable Agreement

Start Date: Jun 1, 2024
End Date: May 31, 2026

Objective:
Ralstonia solanacearum species complex causes bacterial wilt diseases globally in 394 plant species, including food crops such as tomato and potato, and ornamentals including geraniums. Of great concern are race 3 biovar 2 (r3b2) strains of R. solanacearum, capable of causing devastating brown rot of potato at cool temperatures (<25°C). As a result, R. solanacearum r3b2 strains are quarantine pathogens in Europe and Canada and are listed as select agents in the United States. The objective of this research is to use enrichment technology to increase the sensitivity and reliability of detecting low numbers of the select agent pathogen R. solanacearum r3b2 in latently infected geraniums.

Approach:
Determine levels of ten-fold serial diluted R. solanacearum spiked in healthy geranium tissue after enrichment in either a liquid general growth medium or a semiselective medium (containing antibiotics) under at least two enrichment durations. At least one r3b2 and one non-r3b2 strains will be tested in the experiment. Prior-and post-enrichment levels of R. solanacearum will be determined by plating and tested by qPCR using specific primers and probes (Huang lab at USDA/ARS).